PREVALENCE OF FUSION AND GEMINATION IN PERMANENT TEETH IN COPPADOCIA REGION IN TURKEY

Transcription

1 PREVALENCE OF FUSION AND GEMINATION IN PERMANENT TEETH IN COPPADOCIA REGION IN TURKEY 1 AHMET ERCAN SEKERCI, DDS 2 YILDIRAY SISMAN, DDS, PhD 3 YASIN YASA, DDS 4 HALIL SAHMAN, DDS 5 ABDULLAH EKIZER, DDS ABSTRACT The objective of the present study was to determine the prevalence of dental fusion and gemination in permanent teeth in Coppadocia region in Turkey. The distributions of these conditions among different types were also studied. The present study was based on the clinical assessment and panoramic radiographs of 8,229 patients. All of these patients were examined clinically and had radiographs and photographs taken at the time of examination. All data (age, sex and systemic disease or syndrome) were obtained from the patient files and analyzed for double teeth (fusion and geminaiton). The distribution of double teeth was investigated according to types and clinical positions. In this study the prevalence of double teeth (Fusion and gemination) in the permanent dentition in patients between 12 to 60 years was 0.29%. 14(0.17%) were Fused and 12(0.14%) were geminated teeth. The maxillary incisors were the most commonly affected, followed by the mandibular premolars. Fusion and gemanation are uncommon conditions in Turkish population, but they are important dental anomalies that can affect any tooth in the mouth. Recognizing the condition will facilitate the endodontist, prosthodontist, periodontist, orthodontist, and for surgical management of such teeth. Key words: Fusion, gemination, prevalence, permanent dentition INTRODUCTION Fusion has been described as a developmental anomaly characterized by the union of two adjacent teeth. This union of two separate tooth germs may be either complete or incomplete. Fused teeth have separated or shared pulp chambers and canals. 1 There will be one less tooth in the arch than normal if the affected tooth is counted as one 2 (Fig 1: a-d) Gemination is currently recognized as an attempt by a single tooth bud to divide, with a resultant formation of either a large tooth with a bifid crown or two completely divided teeth throughout the crown and root. 3 The normal number of teeth is observed if the affected tooth is counted as one 2 (Fig 1: e, f) Fusion may be differentiated from gemination by the presence of two separate roots or a single root. 4 In cases where union of a normal tooth bud to a supernumerary tooth germ occurs, the number of teeth is also normal and differentiation from gemination may be very difficult. In cases of fusion, the crowns are united by enamel and/or dentine, but there are two roots or two root canals in a single root. In contrast, in gemination, the structure most often presents two crowns, either totally or partially separated, with a single root and one root canal. 5 1 Correspondence to: Ahmet Ercan, SEKERCI, Department of Oral Diagnosis and Radiology, Faculty of Dentistry, Erciyes University, 38039, Kayseri, Turkey. aercansekerci@hotmail.com, Tel: /29227 Fax: Associate Professor and Chair, Department of Oral and Maxillofacial Radiology, Faculty of Dentistry, Erciyes University, Kayseri, Turkey 3 Department of Oral and Maxillofacial Radiology, Faculty of Dentistry, Ordu University, Ordu, Turkey 4 Department of Orthodontics, Faculty of Dentistry, Erciyes University, Kayseri, Turkey 17

2 Fig 1: Typical samples of fused teeth (a-d) and geminated teeth (e, f) The clinician must then depend on both clinical examination and radiographs to make the final diagnosis between fusion and gemination. These types of anomalies may be unilateral or bilateral and may affect either dentition, although the primary teeth are more commonly affected. Bilateral dental fusion in the primary dentition is a rare dental anomaly. 6 Bilateral presentations are less common than unilateral ones (0% to 0.6%). 7 Epidemiological studies have shown that the prevalence of fused teeth was similar for females and males and occurred most frequently in the primary dentition. 30 The etiology of double teeth may be attributed to evolution, trauma, heredity and environmental factors. 31 METHODOLOGY A retrospective observational study was made of all the patients with double teeth seen in the Dental Faculty from 2006 to In the present study 18,216 patients records were evaluated and 8,229 samples were selected. Inclusion and exclusion criteria are presented in Table patients (13 males and 13 females) were found with permanent double teeth ranging in age from 12 to 60 years. (Table 2). Inclusion criteria TABLE 1: ADOPTED CRITERIA FOR SAMPLE SELECTION Exclusion criteria *Permanent dentition *No caries *No radiographic distortions *All permanent teeth exist except third molars on radiographs *Mixed/deciduous dentition *Extensive carious lesion * Radiographs with image distortions *One or more teeth is missing except third molars on radiographs *Fixed prosthodontic restoration 18

3 TABLE 2: DOUBLE PERMANENT TEETH IN 8229 ADULTS N % Total number of double teeth Fusion Gemination Upper jaw Lower jaw Unilateral Bilateral Boys Girls In each case the gender of the patient, the position of the double teeth and of other anomalies in either dentition were noted. A photograph, intra-oral radiograph and/or panoramic radiograph were taken at the time of diagnosis in all cases. Each double tooth case was thereby classified on the basis of its clinical and radiographic morphology, in terms of the number and shape of crowns and roots. Two experienced dentists examined all radiographs. They were reviewed and discussed by the panel in a negatoscope in which an a7x lens was used. Inter-examiner discrepancies were solved by consensus and agreement. The involved teeth were categorized by a method similar to the rule frequently applied in the differentiation between fusion and gemi- TABLE 3: PREVALENCE OF DOUBLE TEETH IN PREVIOUS STUDIES Study Year Country Sample No of Prevalence double teeth (%) Primary Dentition 1 Tinn Great Britain 8, Menczer United States 2, Clayton United States 1, Grahnen Sweden 1, Moller Iceland Curzon Canada (white) Ravn Denmark 4, Holm Sweden Jarvinen Finland 1, Buenviaje United States 2, Magnusson Iceland Barac-Furtinovic V Croatia 2, L Aguilo Spain 6, Cheng RB China 4, Mixed Dentition 15 Mckibben United States Ruprecht Saudi Arabia Salem Saudi Arabia ,08 18 Bruce United States ,35 19 Backman Sweden ,3 20 Chen Wei Taiwan ,72 Permanent Dentition 21 Boyne United States Clayton United States Castaldi Canada Curzon Canada White Indian ,8 25 Hamasha Jordan

4 nation. A tooth was recognized as fused if its crown and root were enlarged and the tooth count was less than one. A tooth was recognized as geminated if its crown was enlarged with a normal root and the tooth count was normal. Both fused and geminated teeth were counted as a double tooth. The distribution of double teeth was investigated according to gender differences, types (fused or geminated), and clinical positions. The positions of the double permanent teeth were studied according to the unilateral arch and the mandibular or maxillary arch. A Pearson chi-squared test was used to determine potential differences in the distribution of double teeth when stratified by gender. RESULTS During the above mentioned time period 8,229 Turkish subjects were reviewed. The data obtained are shown in Table 3. From this data, double teeth were detected in 26 subjects. The sample of 8,228 adults examined showed a prevalence of (0.29%) double teeth, 53.8% of them were fused and 46.2% geminated. From Table 3 shown the anomaly is equally present in males and females with a 1:1 male/female ratio (P<0.001). Furthermore, in regard to distribution in the jaws the anomaly is more frequent in the upper jaw (57.6%) than in the lower jaw (52.4%), and is more frequent unilaterally (91.6%) than bilaterally (8.4%) (Table 3). Bilateral occurrence of double teeth in the maxilla was seen in 2 cases of which were involving the central incisors and supernumerary teeth (Table 4). The analysis of clinical and radiographic characteristics of the double teeth showed three morphological types, large crown with a large root and root canal with labiolingual grooves, two fused crowns with deep labiolingual grooves and two roots and a partially vertical separated large crown with single root and with labiolingual grooves. DISCUSSION Dental anomalies of number and forms may occur in the primary and permanent dentitions. They are frequently observed during routine dental examination, leading to orthodontic problems, such as spacing or crowding of teeth, loss of arch length, esthetic problems, increased caries risk, and deviation of the midline. 31 They may be associated with a syndrome or they can be found in non-syndromic patients. Current data in the literature show that double teeth in the permanent dentition are observed in 0.0~0.8% of the general population with no gender predilection. 16,23,33 In the present study, the prevalence of double teeth in the permanent dentition of patients between 12 to 60 years old was 0.29%. Due to this low prevalence, the importance of these anomalies tends to be underestimated. 34 The etiology of fusion is not exactly known. Some writers contend that fusion results when two tooth germs develop so close together that, as they grow, they come into contact and fuse before calcification. Other researchers believe that physical pressure of force generated during growth causes contact between adjacent tooth germs. Other authors consider a viral infection during pregnancy and the use of thalidomide as possible causes of the anomaly. 35 Although the etiology is still not clear, there is strong evidence suggesting a genetic link as evidenced in family and twin studies. 32,34 Fusion has also been reported with congenital anomalies like cleft lip. 36 It is also see in X- linked congenital conditions. 37 Some dental and nondental abnormalities have been associated with double defects. These include: Supernumerary teeth, hypodontia, peg-shaped permanent maxillary lateral incisors, dens in dente, nail disorders, syndactyly 38, successional conical teeth, macrodontia and double permanent teeth have been recorded following double primary teeth. 39 Kolenc-Fuse 40 reported that genetic linkage and molecular biology studies allowed the identification of the mutations responsible for some patterns of syndromic and non-syndromic tooth agencies. Studying the family history of the cases reported in this article, it was observed that double teeth were not present in patients parents or siblings. The differential diagnosis for fused teeth includes gemination and macrodontia. Several clinical and radiographic benchmarks are used to distinguish fusion from gemination. Fusion is the incomplete attempt of two tooth buds to fuse into one, however gemination is the incomplete attempt of one tooth bud to divide into two. 36 Clinically, the crowns of the teeth appear to be melded together, with a small groove between the mesial and distal sections 41, but on the fused teeth radiographs, two distinct pulp chambers and if the 20

5 fused tooth is counted as one unit, there will be one tooth less in the arch than normal. In cases of gemination, radiographically there in only one pulp chamber and if the anomalous tooth is counted as one unit, the number of teeth in the arch will be normal. Geminaiton may be differential from fusion by the increased number of teeth, except in unusual cases, in which the fusion is between a supernumerary tooth and a normal tooth. Macrodontia is a condition in which the teeth are larger than usual and exhibit normal crown, root and pulpal morphology. 42 Table 3 lists previous studies done on the prevalence for double teeth in the primary dentition as 0.1% to 1.5% (one to fifteen out of 1,000), in the mixed dentition it is 0.3% to 0.72% (three to seventy-two out of 1,000) and, in the permanent dentition it is 0.0% (zero to eight out of 1,000) for unilateral presentation. Hamasha et al 29 reported that maxillary central incisors were the most commonly affected teeth (3.55%) followed by the mandibular third molars (0.91%). However, these results are different from the present study. In this study, double permanent teeth were found mostly in the maxillary central incisors, followed by the mandibular premolars. Aguilo et al 19 reported that double teeth were frequently unilateral, involving two adjacent teeth, and no difference was found in the proportion of double teeth in either the mandible or maxilla, or on the right or left side. This is in agreement with this study. Double teeth may produce esthetic problems and malocclusions, especially when supernumerary elements are included. Since fused teeth are obviously wider than the circumjacent teeth, esthetics may be a concern. When normal teeth fuse, excess dental space can result. This can result in diastema formation. When fusion occurs in the primary dentition, some of the permanent incisors are often not present. These problems require both cosmetic and orthodontic consideration. 43 The presence of fissures or grooves at the union between fused teeth predisposes it to caries and periodontal disease. 44 In a preventive context, the buccal and lingual vertical grooves of the double teeth may be pronounced and difficult to clean, and are highly susceptible to caries. 45 Sealing the grooves with sealant or resin may decrease the risk of caries. The placement of fissure sealants or composite restorations in these grooves should decrease the caries risk. 46 The presence of double deciduous tooth can cause delayed resorption of the root due to greater root mass and increased area of root surface relative to the size of the permanent successor crown. 40 The management of a case of fusion depends on which teeth are included, the level of fusion, and the morphologic result. If the affected teeth are primary, they may be retained as they are. If the clinician intends to extract, it is important to first of all determine whether the corresponding teeth are present. 36 Several reports have suggested that in order to intercept future malocclusion, further treatment, including extraction, partial removal, or separation of double teeth, should be considered. 47 If the fused tooth is free from caries, it may require no particular treatment Universal preventive advice should be given to the parent and the child 10 and if caries already exists, a restoration should be placed in order to retain function and esthetics. 44 If there is pulpal involvement, endodontic treatment should be carried out in the same way as for a multirooted tooth. 48 When dividing double teeth, the complicated dental canal system should be evaluated carefully. Orthodontic and prosthodontics management should be considered to ensure functional occlusion and improve esthetics. CONCLUSIONS Understanding the prevalence of double teeth is very important to the dentists. Fusion and gemination are uncommon conditions, but they are important dental anomalies. These anomalies influence tooth alignment and interdigitation, arch symmetry, appearance, and associated periodontal tissues. Careful treatment planning, including conservative, endodontic, prosthodontics, periodontic and orthodontic considerations are required. The patients expectations and degree of compliance must also be accurately assessed when determining suitable management. REFERENCES 1 Velasco LF, de Araujo FB, Ferreira ES, Velasco LE. Esthetic and functional treatment of a fused permanent tooth: a case report. Quintessence Int 1997, 28: Duncan WK, Helpin ML. Bilateral fusion and gemination: a literature analysis and case report. Oral Surg Oral Med Oral Pathol 1987, 64: Neville BW, Damm DD, Allen CM, Bouqout JE. Oral and Maxillofacial Pathology, 2 nd edition. Philadelphia: Saunders 2002,

6 4 Prabhakar AR, Marwah N, Raju OS. Triple Teeth: A case report of an unusual fusion of 3 teeth. ASDC J Dent Child 2004, 71: Alvarez I, Creath CJ. Radiographic considerations for supernumerary tooth extraction: report of case. ASDC J Dent Child 1995, 62: Milano M, Seybold SV, McCandless, G, Cammarata R. Bilateral fusion of the mandibular primary incisors: Report of case. AS DC J Dent Child 1999, 66: Tinn CA. Excess, deficiency and gemination in the deciduous and permanent dentition of school children. Br Dent J 1940, 68: Menczer LF. Anomalies of the primary dentition. J Dent Child 1955, 22: Clayton JM. Congenital dental anomalies occurring in 3,557 children. J Dent Child 1956, 23: Grahnen H, Granath LE. Numerical variations in primary dentition and their correlation with the permanent dentition. Odontol Revy 1961, 12: Moller P. Oral health survey of preschool children in Iceland. Acta Odontol Scand 1963, 21: Curzon JA, Curzon MEJ. Congenital dental anomalies in a group of British Columbian children. J Can Dent Assoc 1967, 33: Ravn JJ. Aplasia, supernumerary teeth and fused teeth in the primary dentition. Scand J Dent Res 1971, 79: Holm AK, Arvidsson S. Oral health in preschool Swedish children. Odontol Revy 1974, 25: Jarvinen S, Lethinen L, Milen A. Epidemiologic study of joined primary teeth in Finnish children. Community Dent Oral Epidemiol 1980, 4: Buenviaje TM, Rapp R. Dental anomalies in children: A clinical and radiographic survey. J Dent Child 1984, 51: Magnusson TE. Hypodontia, hyperdontia, and double formation of primary teeth in Iceland. Acta Odontaol Scand 1984, 42: Barac-Furtinovic V, Skrinjaric J. Double teeth in primary dentition and findings of permanent successors. Acta Stomatol Croat 1991, 251: Aguilo L, Gandia JL, Cibrian R, Catala M. Primary double teeth. A retrospective clinical study of their morphological characteristics and associated anomalies. Int J Paediatr Dent. 1999, 9: Cheng RB, Chen X, Liu SJ, Pan L, Wu XG. An epidemiological survey of fusion of deciduous teeth of 4,286 kindergarten children in Shenyang city. Shanghai Kou Qiang Yi Xue 2003, 12: McKibben DR, Brearly LJ. Radiographic determination of the prevalence of selected dental anomalies in children. J Dent Child 1971, 38: Ruprecht A, Batniji S, El-Neweihi E. Double teeth: The incidence of fusion and gemination. J Pedod 1985, 9: Salem G. Prevlanence of selected dental anomalies in Saudi children from Gizan region. Community Dent Oral Epidemiol 1989, 17: Bruce C, Manning-Cox G, Stanback-Fryer, C, Banks K, Gilliam M. A radiographic survey of dental anomalies in Black pediatric patients. NDA J 1994, Backman B, Wahlin YB. Variations in number and morphology of permanent teeth in 7-year-old Swedish children. Int J Paediatr Dent 2001, 11: Chen-Wei Wu, Yng-Tzer Lin, Yai-Tin Lin. Double Primary Teeth in Children under 17 years old and Their Correlation with Permanent Successors. Chang Gung Med J 2010, 33: Boyne PJ: Gemination Report of two cases. J Am Dent Assoc 1955, 50: Castaldi CR, Bodnarchuk A, MacRae PD, Zacherl WA. Incidence of congenital anomalies in permanent teeth of a group of Canadian children aged 6-9. J Can Dent Assoc 1966, 32: Hamasha AA, Al-Khateeb T. Prevalence of fused and geminated teeth in Jordanian adults. Quintessence Int 2004, 35: Peyrano A, Zmener O. Endodontic management of mandibular lateral incisor fused with supernumerary tooth. Endod Dent Traumatol 1995, 11: Yeun SWH, Chan JCY, Wei SHY. Double primary teeth and their relationship with the permanent successors: a radiographic study of 376 cases. Pediatr Dent 1987, 9: Tasa GL, Lukacs JR. The prevalence and expression of primary double teeth in western India. ASDC J Dent Child 2001, 68: Hagman FT. Anomalies of form and number, fused primary teeth, a correlation of the dentitions. ASDC J Dent Child 1988, 55: Nik-Hussein NN, Abdul Majid Z. Dental anomalies in the primary dentition: distribution and correlation with the permanent dentition. J Clin Pediatr Dent 1996, 21: Kjaer I. Daugaard-Jensen J. Interrelation between fusions in the primary dentition and agencies in the succedaneous permanent dentition seen from an embryological point of view. J Craniofac Genet Dev Biol 2000, 20: Meadors LW, Jones HL. Fused primary incisors with succedaneous supernumerary in the area of a cleft lip: case report, Pediatr Dent 1992, 14: Global M, Ito M, Hall BD. A new X-linked multiple congenital anomalies/mental retardation syndrome. Am J Med Genet 1984, 17: Killian CM, Croll TP. Primary and permanent incisor twinning defects in one dental quadratn: report of case. Quintessence Int 1990, 21: Brook AH, Winter GB. Double teeth. A retrospective study of geminated and fused teeth in children, Br Dent J 1970, 129: Kolene-Fuse FJ. Tooth agenesis: in search of mutations behind failed dental development. Med Oral Patol Oral Cir Bucal 2004, 9(5): Tannenbaum KA, Alling EE. Anomalous tooth development. Case reports of germination and twinning. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 1963, 16: Chaudry SI, Sprawson NJ, Howe L, Narin RI. Dental twinning. Br Dent J 1997, 182: Alpoz AR, Munanoglu D, Oncag O. Mandibular bilateral fusion in primary dentition: case report. J. Dent Child 2003, 70: Nunes E, de Moraes IG, de Oliviera Novaes PM, de Sousa SMG. Bilateral fusion of mandibular second molars with supernumerary teeth: Case Report Braz Dent J 2002, 13: Himelhoch DA. Separation of fused primary incisors: report of case. ASDC J Dent Child 1988, 55: Mochizuki K, Yonezu T, Yakushiji M, Machida Y. The fusion of three primary incisors: report of case. ASDC J Dent Child 1999, 66: 421-5, Reisenberger RE, Killian CM. Triplication and twinning in one dental arch: report of a case. Quintessence Int 1990, 21: Santos LM, Forte FD, Rocha MJ. Pulp therapy in a maxillary fused primary central incisor report of a case. Int J Paediatr Dent 2003, 13: